15 May 2018

New strain of rabbit calicivirus confirmed in NZ

The problem

Rabbits have been a constant source of trouble for New Zealand since they were first introduced in the 1830s. It's previously been estimated that rabbits cost New Zealand over $50 million in lost production, plus a further $25 million in direct pest control a year.

Wild rabbits:

compete with livestock for pasture by eating the best grass

cause extensive land damage from burrowing, making farming land useless

cause public nuisance and damage to public and private property.

Ongoing management of wild rabbits is essential to New Zealand's economy and environment.

Managing rabbit numbers

New Zealand has a long history of rabbit control. The main methods used to control rabbits are shooting, poisoning, fumigation of burrows, and rabbit-proof fencing. An introduced virus (Rabbit Haemorrhagic Disease Virus) also reduces rabbit numbers.

Under the Biosecurity Act, MPI has a role facilitating coordination among those involved in rabbit control (such as the Rabbit Coordination Group). We also support the development of rabbit control tools through funding programmes.

Rabbit Haemorrhagic Disease Virus (RHDV)

RHDV – also known as rabbit calicivirus – is a virus used as a pest control tool to reduce the number of wild rabbits. It affects the European rabbit (Oryctolagus cuniculus). Rabbits are infected with the virus which then spreads through the population. Once a rabbit shows symptoms, it dies quickly.

Rabbits get the virus:

from direct contact with other rabbits – through their eyes, nose, and mouth

from flies, fleas, and possibly some mosquitos, which can carry the virus.

Urine, faeces, and respiratory secretions may also shed the virus.

Rabbit calicivirus doesn't affect other animals

Calicivirus is a family of virus and there are several types. The 2 most common types in New Zealand are rabbit calicivirus (also known as Rabbit Haemorrhagic Disease Virus) and feline calicivirus – which affects cats.

These 2 viruses are completely different and don't jump between species. RHDV only affects rabbits, it doesn't present a danger to cats, dogs, or any other type of animal.

Rabbits are becoming immune to RHDV1

A Czech strain of RHDV1 strain was illegally introduced to New Zealand in 1997 after an application for its import was declined. Initially, the virus caused a fast and large drop in rabbit numbers. However, in the 20 years since it was first introduced, New Zealand's wild rabbits have become increasingly immune to the RHDV1 strain.

RHDV variant assessed in 2017

In February 2017, the Environmental Protection Authority (EPA) released its decision on an application under the Hazardous Substances and New Organisms (HSNO) Act. The EPA decided the RHDV (K5 variant) is non-hazardous.

RHDV1 K5 is a new strain but it is not a new virus. It's a Korean strain of the existing RHDV1 virus. The RHDV1 virus is already widespread in New Zealand and specific to the European rabbit.

After the EPA decision, MPI still had to approve the use of the virus under the Agricultural Compounds and Veterinary Medicines (ACVM) Act and the Biosecurity Act. The virus could not be imported or used without MPI's approval.

Application for approval to use RHDV1 K5

In February 2018, MPI approved an application from Environment Canterbury to import and release the RHDV1 K5 virus for pest rabbit management. The intention was to introduce the strain nationally.

The virus won't completely fix the wild rabbit problem for New Zealand farmers. But the new virus strain will have an effect on wild rabbit populations and will supplement traditional methods of control.

MPI assessed the potential benefits and impacts of the virus before granting the application. As a result, MPI has imposed a number of conditions to ensure the virus will be securely transported, stored, and used in accordance with strict protocols.

MPI also considered risks to animal welfare and sought independent advice from the National Animal Welfare Advisory Committee (NAWAC). This advice resulted in controls being applied to the sale and use of RHDV1 K5 to address specific welfare concerns.

A nationwide release of the virus will take place over March and April 2018.

Concerns about pet rabbits

MPI acknowledges some domestic rabbit owners have questions about how to protect their pet rabbits from the virus. MPI advises pet rabbit owners to discuss vaccination plans with their veterinarian to ensure their rabbits have the best protection available.

The existing Cylap RCD Vaccine, which has been used in New Zealand for many years to protect domestic rabbits from the current RHDV1 virus, can also be used to protect pet rabbits against the RHDV1 K5 strain. Zoetis, the manufacturer of the vaccine has confirmed that additional vaccine supplies have been made available in New Zealand.

Advice for pet rabbit owners

MPI has responses available for questions we have received about the virus, including how long it takes for immunity to develop in pet rabbits following vaccination.

Find out more

Funding programmes

MPI continues to support the development of humane and effective pest control tools. Since 2012, through the Sustainable Farming Fund, MPI has provided funding for 3 projects relating to rabbit control.

2016 to 2017 funding round

Release strategy for improved RHDV strains to maximise the benefits of rabbit biocontrol

Rabbit Coordination Group

The Rabbit Coordination Group brings key organisations together to improve our management of rabbits in New Zealand. The group includes representatives from regional councils, Federated Farmers, Department of Conservation, Land Information New Zealand, and MPI (and we also provide a secretariat function).